The deposition of latex polymer coatings on solid substrates has long been utilized to impart certain end-use performance properties to those substrates, such as hydrophobicity, strength, adhesive properties, compatibility, and the like. Depending upon the selection of the starting monomers, surfactants, emulsion polymerization conditions, and other parameters, the deposited polymers can be designed to carry an anionic, a cationic, or an amphoteric charge, a feature which directly influences coating performance. Further, the resulting latex polymer can be blended with a range of other functional materials to impart additional or enhanced features to the final coating material.
One particularly useful feature exhibited by cationic latex polymers disclosed in U.S. Patent Application Publication No. 2005/0003163 is their inherent antimicrobial characteristics. Cationic polymers can also be blended with compositions containing small molecule bioactive compounds, species more typically associated with antimicrobial activity, in order to enhance these properties. These antimicrobial components are usually employed in relatively small amounts as formulating ingredients that are added after the polymer has been made. While such blends are useful, many practical issues remain in attempts to enhance or control the extent of antimicrobial protection these compositions might afford. For example, such compositions and methods and are often inadequate for providing long-term protection of materials, especially in their antifungal properties. Methods to augment or to more finely control the antimicrobial properties are also needed. Regulatory issues associated with introducing a new antimicrobial material, namely the polymer, may be significant. Moreover, approaches to prolong or extend the effectiveness of the antimicrobial properties remain elusive.
Therefore, what are needed are new methods and approaches to impart and to enhance antimicrobial activity of latex polymers, as well as the coatings and articles prepared therefrom. What are also needed are methods to more closely manage the antimicrobial activity of such materials, including approaches to extend the effectiveness of their bioactivity.